1. Field of the Invention
The present invention falls into the field of postpress processing; it relates to an apparatus for inserting, collecting or collating two-dimensional products in accordance with the preamble of patent claim 1 and to a method for inserting, collecting or collating two-dimensional products in accordance with the preamble of patent claim 15.
2. Discussion of Related Art
The prior art discloses installations for inserting, collecting or collating products which have a main unit with a conveyor means and a plurality of ancillary units with dedicated drives for supplying products to the conveyor means.
The ancillary units are supply conveyors, for example, and need to have their timing coordinated with respect to one another in order to ensure a desired location for the product they are supplying relative to a predefined position on the conveyor means. Since one and the same supply conveyors have to be used to deliver products of different length to the conveyor means and the distance from one ancillary unit to another ancillary unit is not always optimum in terms of timing on account of physical constraints, appropriate measures need to be taken so as nevertheless to ensure synchronized supply of products to the conveyor means. One such measure is shifting the phase of the supply conveyor, or of the supply conveyors, relative to the phase of the conveyor means. The phase is ideally 100%, that is to say that the operating cycle of the supply conveyors corresponds precisely to the operating cycle of the conveyor means. For the reasons cited above, the operating cycles of the supply conveyors need to be adjusted relative to the operating cycle of the conveyor means. Such a shift in the phase can take place only within an operating cycle of the conveyor means, however. The phase is typically calculated in a central controller or in a drive controller/control system which is associated with each ancillary unit, said central controller and said drive controllers/control systems of the ancillary units being connected to one another via a data bus. To calculate the time of supply, further signals need to be transmitted to the drive controllers/control systems of the ancillary units, which in conventional installations results in numerous signals or data needing to be interchanged between the central controller and said drive controllers/control systems of the ancillary units, said signals often being analogue signals which require appropriate individual connections. Such connecting lines and connectors are generally a possible source of problems for optimum signal transmission, for example on account of electromagnetic incompatibilities, and are therefore accordingly susceptible to interference.
EP 0917 965 B1 discloses an embodiment in which data interchange between a plurality of drive controllers and a central controller is effected exclusively via a bus system, which reduces the number of connections between main and ancillary units. Additional signals are transmitted via the drive controller which is associated with each unit and via an input/output unit, associated with each drive controller, to a bus interface, where they are transferred to the data bus. The data bus therefore firstly transmits data from a preceding setup mode and data corresponding to the analogue signals between the central controller and the individual drive controllers.
The known apparatuses are inadequate in terms of transmission speed and data integrity.